Two melanocortin analogues that are not interchangeable, despite the names.
Melanotan-1 is receptor-selective; Melanotan II is not. MT-1 (afamelanotide) targets MC1R and is approved in some jurisdictions for erythropoietic protoporphyria — as a sustained-release implant, not a reconstituted injection. MT-II hits multiple melanocortin receptors, which is the source of its additional reported effects.
| Melanotan-1 | Melanotan II | |
|---|---|---|
| What it is | Afamelanotide, MT-1, NDP-MSH | MT-2, cyclic α-MSH analogue |
| Evidence tier | Clinical | Preclinical |
| Route | Subcutaneous | Subcutaneous |
| Half-life | ~30 min (implant form is sustained release) | ~1–2 h |
| Vial sizes | 10 mg | 10 mg |
| Water we suggest | standard rule | 3 mL |
| Reported doses | 250 mcg, 500 mcg, 500 mcg | 250 mcg, 500 mcg, 500 mcg |
| Has a schedule | Loading then maintenance | Loading and maintenance phases |
Afamelanotide’s approval covers an implant with completely different pharmacokinetics. The approved dosing does not translate to a reconstituted subcutaneous injection, so treat MT-1 injection figures as community protocol.
MT-II’s activity at receptors beyond MC1R is why it is discussed for effects MT-1 is not. If you are comparing the two, that is the mechanism doing the work.